Torque overload control



April 6, 1954 v GARlK 2,674,357

TORQUE OVERLOAD CONTROL Filed Jan. 3l, 1952 2 Shee't-Sheet l INVENTOR S ERGE GAR! K ATTORNEYS DRIVE 4MOTOR April 6, 1954 s. GARIK 2,674,357

TORQUE OVERLOAD CONTROL Filed Jan. 3l, 1952 2 Sheets-Sheet 2 2. INVENTOR E Vsx-:RGE GARIK BY M+'M ATTORNEYS Patented Apr. (i,r 1954 TORQUE OVERLOAD CONTROL Serge Garik, New York,

search Corporation, ration of New York N. Y., assignor to Re- New York, N. Y., a corpo- Application January 3l, 1952, Serial No. 269,269 4 Claims. (Cl. lim- 56) This invention relates to an improvement in torque overload control devices, and in particular to lock and lock release means for limited torque couples.

An object of this invention is to provide an improved limited torque couple for mechanical drive systems that may be advantageously applied to power wrenches, screw drivers and the like.

A further object of the invention is to provide means for locking a limited torque couple in the disengaged position.

Another object is to provide automatic disengaging means for the locking device.

A further object is to provide such a device which will operate equally well in either direction of rotation.

Another object is to provide such a device that is rugged in construction and readily adaptable to various load and operating conditions.

These and other objects and advantages are provided by the torque overload control device of the invention which generally comprises in combination with a driver member, a driven member and a detent carried by one of said members spring urged into engagement with the other of said members and disengaged therefrom at a predetermined torque load, a locking member carried by said one of said members for holding the detent in disengaged position, and means actuated by axial movement of the driven member for freeing the detent from the locking member.

The invention will be more particularly described with reference to the illustrative embodiment shown in the accompanying drawings in which:

Fig. 1 is a sectional plan view of a limited torque couple embodying the principles of the invention;

Fig. 2 is a fragmentary sectional view of the device shown in Fig. 1 with the driver and driven members locked in the disengaged position; and

Figs. 3 through 6 are fragmentary sectional views of the lock disengaging mechanism in various stages of operation.

With reference to the drawings, I is the driver member of a limited torque couple. It is provided at one end with a boss I2 to receive a drive shaft, not shown in the drawings, connected to any suitable drive motor. The driven portion of the couple generally comprises a shaft I4 axially mounted for rotation within the driver member I ll by bearings I 6. The forward end of the driven .shaft I4 carries the lock release mechanism I8 to be more particularly described hereinafter.

Radially carried in spaced recesses in the driver member IIi of the torque couple are a plurality of spring urged `detents 22. Each detent generally comprises a plunger 2I provided with a head 2li and base 26. The plungers are retained in the recesses 2B by retaining caps 28. Coil springs 3) bear at one end against the retaining caps 28 and at the other end against the bases 2t of the plungers whereby the plungers are urged radially inwardly. At the inward end or" the plungers are spherical members 32 which in normal operation engage sockets 34 in the driven shaft i4. The sockets 34 are more clearly shown in Fig. 2 oi the drawings.

It will thus be seen that under normal loads, power is transmitted from the driver member through the spheres 32 to the driven shaft I4, and when the load increases beyond a predetermined amount, the spheres 32 are forced from the sockets against the spring 30 and the driver member rotates about the driven shaft I4. This torque path is shown by arrows in Fig. 1 of the drawings.

The power transmitting limit of the torque couple may be variously controlled, for example by the number of detents employed in the couple, the force of the springs 3U, and the depth of the sockets 34 in the driven shaft. Thus it will be seen that the power which may be transmitted may be readily varied by merely adjusting the position of the retaining caps 28 in the recesses 2D of the driver member.

Limited torque couples of the above described form have not proved entirely satisfactory in a large number of applications because of generation of heat in the couple after overload conditions have develcped and the strong knocking action caused by the torque transmitting spheres engaging and disengaging the ball sockets in the driven member when overload conditions are encountered.

It has been found that if such overload controls are used in torque tools for tightening nuts and bolts or the like the knocking action will, due to momentum of the rotating parts, tend to tighten the work piece beyond the preselected torque.

To overcome these disadvantages a locking mechanism has been provided which will automatically retain the detents 22 in the disengaged position and prevent action of the springs 30 upon the torque transmitting sphres 32 of detents 22.

The locking mechanism generally comprises a sleeve St which is slidably secured to the portion vof the couple which carries the spring biased detents 22. The sleeve 3B is provided with'openito' the stub shaft 48.

Fig. 3 ofthe drawings.

of detents 22 ings 38 having shoulders 40 for each of the detents.

The shoulders 40 are adapted to slip under the heads 24 of the detents when the detents are in the disengaged position as shown in Fig. 2 of the drawings.

The locking sleeve is urged into the locked position by .coil springs 42, one of which is shown in Fig. 1.

To release the detents, and reengage the torque couple, the sleeve 36 is urged rearwardly against the force of springs 42, this operation being accomplished by the lock release mechanism |8. The lock release generally comprises a sleeve 44 which is secured by bolt 46'to "a'stubshaftAS slidably mounted on the tool receiving en'd ofthe driven shaft I4, by means of a set screw 50.

The set screw 50 preventsspring 52 'froml pushing the lock release mechanism from the. driven shaft I4, and in the form of construction shown in the drawings transmits torque from shaft I4 It is evident, however, that sleeve 44 and stub shaft A48 vmay be constructed A coil spring 52,`mounted in a recess 54 in the end of shaft I4, urges the stub shaft and lock releasing sleeve 44 forwardly, which permits'the rounded noseof the plunger 56 of spring loaded detentsz58 to'project into space60 as shown in 'It is evident that the round nose plunger 56"may be replaced with a spherical member of'suitable size. Axial movement of the sleeve'44 ina rearward direction against the vtension 'of spring 52 will urge the detents 56 and the locking sleeve rearwardly to release the detents therefrom.

The operation of the locking'sleeve and' release 'mechanism will be more readily apparent from the following description or" a cycle of operation of the'device.

'In 'operation of the device, for example, as a power operated torque tool, a screwdriver or socket wrench isA attached tothe end of the stub shaft 48, andthe tool is vpressed into engagement with'the work so that sleeves 44 and 35 are urged rearwardly and power is'transmitted :from the drive motor through the torque couple to the tool.

These conditions are shown in Fig. 1 of the drawings and it willbe seen that as long as detents 22 are in their engaged position, springs 42 cannot force'thelocking sleeve 35 forwardly as shoulders 40 are'in contact with the heads 24 of the detents 22. However, as soonas the preselected torque limit is reached, the heads '24 will be clear of shoulders 40 of the locking sleeve and the sleeve will be moved forwardly by springs 42 to hold detents 22 in their outward position as is clearly shown in Fig. '2 vof the drawings.

Withthe sleeve 36 in the detent locking position, the detents'53 are compressed radially outwardly by the 'lock releasing sleeve 44. When the power tool is disengaged from the working piece, spring`52 urges the stub shaft 48 and the lock release sleeve V44 forwardly permitting the plungers 56 of -detents 58 to enter channel ,60 as shown in Fig. B-andthe power tool is ready to .be broughtinto engagement with thenext work piece. ,As the tool head is forced'into Aengagement with the Work piece, spring 52 is compressed and stub shaft 48y and sleeve .44 are urged rearwardly. This axial movement of sleeve 44 vpushes plunger 56 and in turn locking sleeve '.36 axially rearwardly as shown inFigs. #land 5 of `forced from the space the drawings. In the position shown in Fig. 5, the sleeve 36 is at its greatest rearward displacement and detents 22 are released from shoulders 4U so that power is transmitted from the drive motor to the work piece. Plungers 56 are forced out of the space 60 by the action of the sloping end wall 62 as the rearward axial movement of the lock release 44` is continued. In Fig. 3 of thedrawings the plunger `is fully :extended into space 60, in Figs. 4 and 5 the plunger is being 60 and in Fig. 6 the plunger is fully retracted and lock releasing sleeve 44 Vis approaching its maximum rearward travel.

With the Adetents in this position the locking sleeve 36 is"set,`that is, as soon as a torque overload'condition arises, sleeve 36 is free to move forward under the urging of springs 42, plungers 156. sliding Vover thefsurface of the lock releasing anism. yFor example, both the locking sleeve and the lock release-mechanism may rbe'provided on one member of the torque couple, or thelocking sleeve may be carried by the'driven member vand lock release mechanism by the'driver'member.

I claim:

A1. A torque overload control device comprising, in combination with a driver member, ra driven'member Vand a detent carried by one of said membersspring urged into engagement with the other of 'said'members and disengaged' therefrom at a predetermined torque load, a locking member carried by said one ofsaid members 'said locking lmember including 'detent engaging means adapted to hold'the detents in the disengaged position yout of contact with the other of rsaid members, springmeans urging vthe locking member into locking position-to engage'the detent, a lock release detent carried by the locking member, a stubshaft sldably vcarried by said driven member, Yand means actuated by axial movement of said stub shaft for actuating the lock release detent when the locking member is in engagement with the detent.

2. A torque overload control device comprising, in combination with a driver member, a driven member and a detent carried by one of `said members spring urged into engagement withthe other'of'saidmembers and disengaged therefrom at a predetermined torque load, .a

means actuated by axial movement of the stub vshaftfor operatingfthe lock release member to free the detent from said locking member.

'3. lAtorque overload .control device vcomprising, in -combination with a driver member, a

-driven 'member and a 4detent vcarried'by one of said members'spring' urged into engagement with :the other ofsaiii members 'anddisengaged'therefrom at a predetermined torque load, a locking member carried by said one of said members, said locking member slidably mounted for movement between a locking position for holding the detent in disengaged position to an unlocking position to free the detent, a lock release member carried by one of said members, a stub shaft slidably carried by the driven member and means actuated by axial movement of the stub shaft for operating the lock release member to free the detent from said locking member.

4. A torque overload control device comprising in combination with a driver member, a driven member, and a detent radially carried by the driver member spring urged into engagement with the driven member and disengaged therefrom at a predetermined torque load, a locking sleeve carried by the driver member, said locking sleeve being slidably mounted for movement between a locking position for holding the detent in the disengaged position to an unlocking position to free the detent, spring means urging the locking sleeve into locking position, a stub shaft slidably carried by the driven member, a lock release member secured to the stub shaft whereby the locking sleeve is urged into the unlocked position against the tension of the spring means by axial movement of the stub shaft.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,263,709 Van Sittert Nov. 25, 1941 2,401,992 Waller June 11, 1946 2,412,630 Nelson Dec, 17, 1946` 2,497,893 Lnahan Feb. 21, 1950 2,537,672 James Jan. 9, 1951 

